JP3609622B2 - Capacitor charge / discharge ignition system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a capacitor charge / discharge igniter used for a two-cycle engine or the like.
[0002]
[Prior art]
A capacitor charge / discharge igniter for use in a brush cutter or other small two-cycle engine has a permanent magnet on the rotor side and two magnetic poles arranged on both sides of the permanent magnet in the rotational direction. And an iron core having a pair of legs is provided on the fixed side corresponding to the rotor, and a generator coil is provided on the anti-entrance side in the rotational direction of the rotor, that is, on the exit side, of the pair of legs of the iron core. Using the first output in the negative direction and the second output in the positive direction that are sequentially induced in the power generation coil when the rotor is rotated, the capacitor is charged by the second output in the positive direction, and the negative direction The switching element is turned on by the first output to discharge the capacitor charge to the ignition coil, and a high voltage is generated by the ignition coil for ignition.
[0003]
This ignition device has a problem that the generation time of the first output in the negative direction induced in the power generation coil cannot be increased because the power generation coil is located on the outgoing leg in the rotational direction of the rotor, and the advance angle cannot be increased. .
[0004]
Therefore, in the conventional ignition device, a pickup coil system in which a pickup coil is provided at the leg portion on the iron core entry side, and a protruding portion that protrudes on the opposite side to the rotation direction of the rotor is provided at the tip portion of the leg portion on the iron core entry side. The lead angle characteristic is improved by adopting a deformed iron core system or a circuit system by circuit processing, etc., and extending the generation time of the first output in the negative direction.
[0005]
[Problems to be solved by the invention]
Each of the conventional ignition devices has the following drawbacks. That is, in the pickup coil system, since it is necessary to provide a pickup coil in addition to the power generation coil on the iron core, there is a disadvantage that the structure is complicated and the manufacturing cost increases.
[0006]
Also, in the deformed core method, there is a protruding part at the tip of the leg, so when manufacturing iron cores by laminating core pieces punched with magnetic steel sheets and other materials, the yield of the material at the time of punching the core pieces becomes poor. At the same time, there are disadvantages that the projecting portion becomes heavier as a whole, requires a large mounting space on the engine side, and cannot secure a sufficient advance angle width. Further, the circuit system has a disadvantage that the circuit configuration is complicated and expensive, the substrate on which circuit elements are mounted becomes large, and the size is increased.
[0007]
In view of such conventional problems, the present invention provides a capacitor charging / discharging ignition device that can ensure a large advance angle with a simple structure and can be reduced in size and weight as a whole, and can be manufactured easily and inexpensively. The purpose is to provide.
[0008]
[Means for Solving the Problems]
The present invention includes a rotor 1 provided with two magnetic poles 5 and 6 that are different in the rotational direction, an iron core 7 having a pair of legs 8 and 9 and provided on the fixed side corresponding to the rotor 1, and a one generating coil 10 wound around the leg 9 side of the core 7, the positive direction of the output V ₂ of the generator coil 10 charges the capacitor 15, the negative going output V ₁ of the power generation coil 10 In the capacitor charge / discharge type ignition device in which the switching element 19 is turned on to discharge the electric charge of the capacitor 15 to the ignition coil 16, of the pair of leg portions 8 and 9 of the iron core 7, the rotor 1 enters the rotation side. by placing the generator coil 10 to the leg 9 of the negative direction of the output V ₁ of the occurrence time T with longer generating coil 10, the trigger circuit 20 to trigger the switching element 19 by the negative direction of the output V ₁ a Torigatai during high speed rotation consists of a capacitor 23 resistor 24 and 25 Constitute a differentiating circuit 22 to move the retard direction ring.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the drawings.
[0010]
The drawings illustrate one embodiment of the invention. In FIG. 1, reference numeral 1 denotes a rotor, which is fixed to an end portion of an engine crankshaft. The rotor 1 is provided with a permanent magnet 2 and a pair of magnetic pole pieces 3 and 4. The permanent magnet 2 is arranged so that the N pole and the S pole face the rotation direction of the rotor 1. Each pole piece 3, 4 is flush with the outer peripheral surface of the rotor 1 on the outer peripheral side, and has N and S poles at positions spaced apart in the rotational direction (direction indicated by the arrow X) on the outer peripheral surface side of the rotor 1. 5 and 6 are magnetically coupled to the north and south poles of the permanent magnet 2.
[0011]
A U-shaped iron core 7 has a pair of leg portions 8 and 9 and is fixed to the fixed side of the engine corresponding to the rotor 1. There is a minute gap between the tips of the leg portions 8 and 9 of the iron core 7 and the outer peripheral surface of the rotor 1, the distance between the pair of leg portions 8 and 9 of the iron core 7, and the pair of magnetic pole pieces 3 and 3. The interval between 4 is substantially the same. Reference numeral 10 denotes a power generation coil, which is wound around a leg portion 9 on the entry side in the rotational direction of the rotor 1 out of the pair of leg portions 8 and 9 of the iron core 7.
[0012]
Generating coil 10, as shown the voltage waveform in FIG. 3 (A), the third output with the rotation of the rotor 1 first output V ₁ of the negative direction and the second output V ₂ of the positive direction of the negative direction V ₃ is sequentially generated, and the generation time T of the first output V ₁ is lengthened by winding around the leg portion 9 on the approach side in the rotation direction of the rotor 1.
[0013]
An ignition control circuit 11 is connected to both ends of the power generation coil 10 as shown in FIG. The ignition control circuit 11 includes diodes 12, 13, 14, a capacitor 15, an ignition coil 16, a spark plug 18, an SCR 19, a trigger circuit 20, a reverse wave processing circuit 21, and the like. The capacitor 15 is used for charging and discharging, and is charged through the charging circuit from the power generating coil 10 to the diode 14, the capacitor 15, the primary side of the ignition coil 16, and the diode 13 by the second output V ₂ of the power generating coil 10. It is like that.
[0014]
The SCR 19 constitutes a switching element for discharge, and is connected in series to a discharge circuit including the capacitor 15 and the primary side of the ignition coil 16, and this SCR 19 becomes conductive when the trigger terminal is triggered, The electric charge of the capacitor 15 is discharged through the primary side of the ignition coil 16.
[0015]
The ignition coil 16 includes a primary side and a secondary side, and a high voltage is generated on the secondary side when the discharge current of the capacitor 15 flows on the primary side. The secondary side is connected to the spark plug 18.
[0016]
Trigger circuit 20, when the first output V ₁ of the power generation coil 10 has reached a predetermined trigger level, adapted to trigger the trigger terminal of SCR19, and differentiating circuit 22 is provided in the trigger circuit 20 Yes. The differentiation circuit 22 includes a capacitor 23 connected in series between the power generation coil 10 and the trigger terminal of the SCR 19, and two resistors 24 and 25 connected between both ends of the capacitor 23 and the ground side. It includes, and is configured to control so as to move the retard direction than trigger timing t _1, t ₂ during rotation of the following medium speed trigger timing t ₃ during high speed rotation. Head wave processing circuit 21 is for causing the third output V ₃ of the negative induced in the generating coil 10 immediately after the positive direction of the second output V ₂ is bypassed to the ground.
[0017]
In the ignition device configured as described above, when the rotor 1 rotates in the X arrow direction by the operation of the engine, the permanent magnet 2 and the magnetic pole pieces 3 and 4 of the rotor 1 pass in the vicinity of the iron core 7 in the X arrow direction, induced in each voltage are sequentially alternating between the third output V ₃ of the first output V ₁ of the negative direction as shown in (a) and the positive direction of the second output V ₂ in the negative direction 3 to the power generation coil 10 . When the second output V ₂ in the forward direction is induced, the diode 14, the capacitor 15, the primary side of the ignition coil 16, via the charging circuit of a diode 13, a charging current flows into the capacitor 15, in FIG. 3 (B The capacitor 15 is charged as shown in FIG.
[0018]
The power generation coil 10 induces a second output V ₃ in the negative direction following the second output V ₂ in the positive direction. This third output V ₃ is bypassed to the ground side via the reverse wave processing circuit 21. Let it process. Therefore, the third output V ₃ is processed as shown by the dotted line in (A) of FIG. 3, is not this by such trigger terminal of SCR19 is triggered.
[0019]
After the capacitor 15 is charged by the second output V ₂ , the rotor 1 rotates approximately once, the pole piece 3 side enters the leg 9 side of the iron core 7, and passes through the distal end side of the leg 9, thereby generating the coil 10. first output V ₁ of the negative direction is induced in. When the induced voltage of the first output V ₁ rises to the trigger voltage V _T of the SCR 19, the trigger circuit 20 triggers the trigger terminal of the SCR 19, the SCR 19 becomes conductive, and the charge of the capacitor 15 is changed between the SCR 19 and the ignition coil 16. Discharge occurs through the discharge circuit on the primary side, and a discharge current flows to the primary side of the ignition coil 16. For this reason, a high voltage is induced on the secondary side of the ignition coil 16, and a predetermined spark is generated in the spark plug 18 to ignite.
[0020]
Although this ignition device ignites by such an ignition operation, since the power generation coil 10 is provided in the leg portion 9 on the entry side of the rotor 1 among the pair of leg portions 8 and 9 of the iron core 7, the first output is provided. There is an advantage that the generation time T of V ₁ can be lengthened, whereby the advance angle width at the time of ignition can be increased with a simple structure. In particular, since it is sufficient to provide a power generating coil 10 on the legs 9 of the entry side of the rotor 1, size of the entire apparatus as compared with the conventional, can in weight, can advantageously be easily and inexpensively manufactured.
[0021]
That is, the magnetic flux φ ₀ of the permanent magnet 2 normally flows in the magnetic path of the permanent magnet 2, the magnetic pole piece 3, the magnetic pole piece 4, and the permanent magnet 2 as shown by the solid line in FIG. When 3 approaches the leg 9 side of the iron core 7, the magnetic flux φ ₁ of a part of the permanent magnet 2 extends from the permanent magnet 2 to the magnetic pole piece 3, the leg 9, the magnetic pole piece 4, and the permanent magnet 2 as indicated by the dotted line. Flowing through the road. Then, as the rotation of the rotor 1 proceeds, the magnetic flux φ ₁ passing through the leg portion 9 increases, and when the pole piece 3 corresponds to the tip of the leg portion 9 as shown in FIG. The magnetic flux φ ₀ passes through the leg 9 and becomes the maximum, and thereafter, the magnetic flux gradually decreases.
[0022]
For this reason, the first output V ₁ starts to be induced in the power generation coil 10 from an early point, and the level of the induced voltage of the first output V ₁ increases as the magnetic flux passing through the leg 9 increases, and the magnetic flux decreases. level of the first induced voltage of the output V ₁ with the go low. Therefore, the generation time T of the first output V ₁ induced in the power generation coil 10 extends to about 1.5 to 2 times as compared with the case where the power generation coil 10 is provided on the counter-ingress side leg 8, and is extremely high. become long, it is possible to generate time T of the first output V ₁ is to increase the advance width of ignition by a long minute.
[0023]
Further, in this ignition device, since the trigger circuit 20 is constituted by the differentiation circuit 22, it operates as shown in the waveform diagram of FIG. 5, and the conduction timing of the SCR 19 can be controlled in accordance with the engine speed. Rotation can be prevented.
[0024]
5, voltage _{V c} is the voltage across the capacitor 15, the voltage _{V a} indicates the voltage at point a side of the differential circuit 22. The current C _i indicates the charging / discharging current of the capacitor 23, the voltage C _V indicates the voltage across the capacitor 23, the voltage V _b indicates the voltage on the point b side of the differentiating circuit 22, and the solid line of each waveform indicates the low speed rotation of the engine. Time and dotted lines are for medium speed rotation, and alternate long and short dash lines are for high speed rotation.
[0025]
When the first output _{V 1} of the power generation coil 10 is generated, the generating coil 10, capacitor 23, resistor 25, via the diode 12, a charging current flows into the capacitor 23 of the differentiating circuit 22, the capacitor 23 is in the first output _{V 1} Charges to near peak. After the charging is completed, the electric charge of the capacitor 23 is discharged from the capacitor 23 through the discharging circuit of the resistor 24 and the resistor 25, and the point b, that is, the trigger terminal is reverse-biased by the voltage _CV across the capacitor 23 during the discharging.
[0026]
In the differentiation circuit 22 at this time, because the time constant of the capacitor 23 and resistor 24, 25 is fixed, during low speed and medium-speed rotation of the engine, Ru can sufficiently discharge the capacitor 23. Therefore, the voltage V b at the point _b of the differentiating circuit 22 changes with the increase in the first output V ₁ of the power generation coil 10 as if there is no differentiating circuit 22 as shown by the solid and dotted lines in FIG. The trigger timings t ₁ and t ₂ for triggering are moved. Therefore, in the process in which the engine speed increases from the low speed to the medium speed, the ignition timing can be advanced according to the change in the speed.
[0027]
When the engine speed increases from medium speed to higher speed, the first output V ₁ of the power generation coil 10 also increases, and the charging current and the voltage C _V across the capacitor 23 are also indicated by a one-dot chain line in FIG. Each increases. Even this reason begin to discharge the capacitor 23 after the first output V ₁ peak, not finished discharges its charge until the first output V ₁ of the following occurs, b by the voltage across C _V of the capacitor 23 The reverse bias of the point becomes deeper.
[0028]
Therefore, when the first output V ₁ of the following occurs, will be the voltage V _b at point b from the reverse bias state rises, rising up to the trigger voltage of the voltage V _b of the point b is suppressed during high-speed rotation the trigger timing _{t 3} when triggered moves the retard direction SCR19 to. For this reason, in the high-speed rotation region of the engine, the conduction timing of the SCR 19 is delayed, and the ignition timing can be retarded.
[0029]
That is, when the trigger circuit 20 of the SCR 19 does not have the differentiation circuit 22 and the trigger circuit 20 is configured by combining two resistors, the ignition timing in the high speed rotation region is advanced as shown by the dotted line in FIG. The engine may overspeed. However, by providing the differentiating circuit 22 and appropriately setting the time constant thereof, the ignition timing in the high speed rotation region can be delayed and kept substantially constant as shown by the solid line in FIG. 6 to prevent engine overspeed. . Since the differentiation circuit 22 is composed of the capacitor 23 and the two resistors 24 and 25, the structure is simple and can be implemented easily and inexpensively.
[0030]
Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment. For example, the iron core 7 only needs to have a structure including a pair of leg portions 8 and 9, and may be an integral U shape or a combination of a plurality of them. When the generator coil 10 is provided on the leg 9 on the entry side of the iron core 7, it is generally stored in a protective case and filled with a filler to solidify, but other structures may be adopted. good.
[0031]
A control element other than the SCR 19 may be used as the switching element. It is free to add functions other than those exemplified in the embodiment to the trigger circuit 20.
[0032]
The rotor 1 may be provided with two magnetic poles 5 and 6 at a predetermined interval in the rotation direction, and is limited to a configuration in which the permanent magnet 2 and the two magnetic pole pieces 3 and 4 are combined. is not. In addition, although the distance between the tip side of the pair of leg portions 8 and 9 of the iron core 7 and the distance between the two magnetic poles 5 and 6 on the rotor 1 side are substantially the same in the embodiment, it is not necessarily required to be the same. Absent. For example, the interval between the pair of leg portions 8 and 9 may be longer than the interval between the magnetic poles 5 and 6 on the rotor 1 side, and conversely, the interval between the pair of leg portions 8 and 9 may be set on the rotor 1 side. It may be shorter than the interval between the magnetic poles 5 and 6.
[0033]
【The invention's effect】
In the present invention, the pair of legs 8, 9 of the core 7, by disposing a generating coil 10 on the legs 9 of the entrance side in the rotational direction of the rotor 1, the time of occurrence of the negative going output of the generator coil 10 Differentiating the trigger circuit 20 that triggers the switching element 19 with the output V _{1 in the} negative direction, and includes a capacitor 23 and resistors 24 and 25, and moves the trigger timing during high-speed rotation in the retarded direction while increasing T because constituted by circuit 22, it can be ensured a greater advance width with a simple structure, miniaturization of the whole device, is capable of weight reduction, an advantage of easily and inexpensively manufactured. In addition, the ignition timing during high-speed rotation can be controlled to be substantially constant.
[0035]
Since the further the capacitor voltage of the fine frequency circuit 22 is configured so as to reverse bias the switching element 19, easily and inexpensively manufactured with a simple circuit configuration.
[Brief description of the drawings]
FIG. 1 is a front view of an ignition device showing an embodiment of the present invention.
FIG. 2 is a circuit diagram of an ignition control circuit showing an embodiment of the present invention.
FIG. 3 is a waveform diagram showing an embodiment of the present invention.
FIG. 4 is an operation explanatory diagram showing an embodiment of the present invention.
FIG. 5 is a waveform diagram showing one embodiment of the present invention.
FIG. 6 is an advance angle characteristic diagram showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor 5,6 Magnetic pole 7 Iron core 8,9 Leg 10 Electric power generation coil 15 Capacitor 16 Ignition coil 19 Switching element (SCR)
20 Trigger circuit 22 Differentiation circuit 23 Capacitors 24 and 25 Resistance V ₂ Output V in the positive direction V ₁ Output T in the negative direction T Occurrence time

Claims (3)

Rotor (1) provided with two magnetic poles (5) and (6) that differ in the direction of rotation, and a pair of legs (8) and (9), provided on the fixed side corresponding to the rotor (1) was a core (7), and a one leg (9) wound on the side wound on the generator coil of the iron core (7) (10), the positive direction of the capacitor by the output V ₂ of the generator coil (10) (15) charges, negative going output V ₁ by the switching element (19) and by conducting the capacitor (15) capacitor charging and discharging the electric charge was to discharge the ignition coil (16) of the generator coil (10) in formula ignition device, of the core (7) a pair of legs (8) (9), by placing a generating coil (10) to the legs of the entry side of the rotational direction of the rotor (1) (9), with lengthening the negative direction of the output V ₁ of the occurrence time T of the generator coil (10), the negative direction of the output V ₁ of the trigger circuit for triggering the switching device (19) (20), a capacitor (23) and become from the resistor (24) (25) Speed rotation when the capacitor charge and discharge type ignition device, characterized in that constituted by a differentiating circuit for moving the retard direction trigger timing (22). The capacitor charging / discharging ignition device according to claim 1, wherein the switching element (19) is reverse-biased by the capacitor voltage of the differentiation circuit (22) . The distance between the pair of legs (8) (9) of the iron core (7) and the distance between the pair of magnetic pole pieces (3) (4) of the rotor (1) are substantially the same. The capacitor charging / discharging ignition device according to 1 or 2.

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